The cutting of pipe to obtain specified lengths is well known. However, in certain situations it is impossible to determine with accuracy the length of pipe which is needed to complete the task. For instance, when drilling wells the final length of casing cannot be determined until the casing string has been run into the bore hole. Thus, the final section of casing is cut when vertically disposed within the bore hole because of the inefficiency in withdrawing the section, laying it horizontal, cutting the casing and then rerunning the section into the bore hole.
To eliminate this inefficiency, it has been the practice in the drilling industry to use a cutting torch for cutting the casing. This however requires that the casing be machined to correct for any irregularities along the cut periphery so that well head apparatus, such as flanges, casing spools and casing heads may be properly attached to the casing. Further, the casing quite frequently has drilling mud and other fluids disposed therein so that as the casing is cut the fluids flow out from within the casing and extinguish the torch. Further, in the drilling of oil and gas wells, it is not desireable to have an ignited cutting torch at the well head where gas leaks could cause fires. Further, when using a cutting torch to cut the vertically disposed pipe, it is extremely difficult to obtain a uniformly disposed cut around the pipe. This is especially true when one realizes that the diameter of well casing may be from two inches to about ten or more feet.
Accordingly, it is an object of the present invention to provide a method of and apparatus for cutting substantially vertically disposed pipe.
Further, it is an object of the present invention to provide a method of and apparatus for cutting substantially vertically disposed pipe along a desired cutting plane at a predetermined distance from a receiving member which mounts a cutter in the cutting plane.
Further, it is an object of the present invention to provide a method of and apparatus for cutting substantially vertically disposed pipe with apparatus which eliminates the fire hazard of an ignited torch.
Further, it is an object of the present invention to provide a method of and apparatus for cutting substantially vertically disposed pipe which uses a cutting element and a single means for moving the cutting element for use over a wide range of pipe diameters.
More particularly, it is an object of the present invention to provide a method of and apparatus for cutting vertically disposed well casing.
Further, it is an object of the present invention to provide a method of and apparatus for cutting substantially vertically disposed well casing at a predetermined distance above a casing head flange so that various well head apparatus my be attached thereto without interference from said casing.
Further, it is an object of the present invention to provide a method of and apparatus for cutting substantially vertically disposed well casing with apparatus which eliminates the fire hazard of an ignited torch.
Further, it is an object of the present invention to provide a method of and apparatus for cutting substantially vertically disposed well casing which uses a cutting element and a single means for moving the cutting elememt for use over a wide range of casing diameter.
In accordance with the invention a method of and apparatus for cutting substantially vertically disposed pipe, such as well casing disposed within a bore hole, is disclosed. A receiving member is positioned around the pipe at a predetermined distance from a desired cutting plane. A cutting element is mounted on a frame for moving circularly around and radially toward the pipe and supports mounted on the frame for locating the cutting element a predetermined distance from the receiving member while supporting the frame uniformly about the pipe. The frame is then positioned around the pipe and the supports are mounted on the receiving member to locate the cutting element within the desired cutting plane. The frame is then prevented from moving relative to the vertically disposed pipe and the cutting element is moved circularly around and radially toward the pipe to cut the pipe along the desired cutting plane at the predetermined distance from the receiving member.